When Uhura confronts the leader of the females, she gives in and shows Uhura the past using a device that they have a specific name for. Even though the leader never calls the device by its name, Uhura uses the name when asking if it can locate the men.
Spock reaches out telepathically to Christine Chapel. This ability was previously established in the original series episode "The Omega Glory" in which Spock "makes a suggestion" to a native girl to open a communicator,, Additionally,,Lt. Uhura is right beside Christine but she doesn't "hear" Spock.. In the original series episode "Return To Tomorrow" Spock's consciousness is briefly in Nurse Chapel's body. In her words, "We shared consciousness". This made it possible for her to receive his thoughts.